Atomized picoscale composition aluminum alloy and method thereof

Abstract

The invention is a process for manufacturing a nano aluminum/alumina metal matrix composite and composition produced therefrom. The process is characterized by providing an aluminum powder having a natural oxide formation layer and an aluminum oxide content between about 0.1 and about 4.5 wt. % and a specific surface area of from about 0.3 and about 5 m 2 /g, hot working the aluminum powder, and forming a superfine grained matrix aluminum alloy. Simultaneously there is formed in situ a substantially uniform distribution of nano particles of alumina. The alloy has a substantially linear property/temperature profile, such that physical properties such as strength are substantially maintained even at temperatures of 250° C. and above.

The invention claimed is: 
     
       1. A process for making an aluminum alloy comprising:
 a) providing an aluminum composite powder having an aluminum microstructure with an ultra-fine grain size and aluminum oxide particles distributed throughout the aluminum microstructure; and 
 b) mixing a ceramic particulate with the aluminum powder to form a powder mixture, the ceramic particulate is selected from the group consisting of silica, silicon carbide, boron carbide, boron nitride, titanium oxide, titanium diboride, and mixtures thereof. 
 
     
     
       2. The process of  claim 1 , wherein the powder mixture comprises about 5 wt. % to about 40 wt. % of the ceramic particulate. 
     
     
       3. The process of  claim 1 , wherein the ceramic particulate is boron carbide having a particle size distribution of 100% less than about 250 microns and the boron carbide is nuclear grade. 
     
     
       4. The process of  claim 1 , wherein the aluminum composite powder has a particle size that is less than about 30 microns. 
     
     
       5. The process of  claim 1 , wherein subsequent to step b), the powder mixture is sintered to form a billet. 
     
     
       6. The process of  claim 5 , wherein the billet is subsequently extruded. 
     
     
       7. The process of  claim 1 , wherein the ultra-fine grain size is about 200 nm. 
     
     
       8. An aluminum alloy comprising a sintered blend of:
 an aluminum composite powder having an aluminum microstructure with an ultra-fine grain size; and 
 a ceramic particulate selected from the group consisting of silica, silicon carbide, boron carbide, boron nitride, titanium oxide, titanium diboride, and mixtures thereof. 
 
     
     
       9. The aluminum alloy of  claim 8 , wherein the sintered blend comprises about 7 wt. % to about 40 wt. % of the ceramic particulate. 
     
     
       10. The aluminum alloy of  claim 8 , wherein the ceramic particulate is boron carbide having a particle size distribution of 100% less than about 250 microns and the boron carbide is nuclear grade. 
     
     
       11. The aluminum alloy of  claim 8 , wherein the aluminum composite powder comprises aluminum oxide particles distributed throughout the aluminum microstructure. 
     
     
       12. The aluminum alloy of  claim 11 , wherein the oxide content of the aluminum composite powder ranges from about 0.1 wt. % to about 4.5 wt. %. 
     
     
       13. The aluminum alloy of  claim 11 , wherein the ultra-fine grain size is about 200 nm. 
     
     
       14. The aluminum alloy of  claim 8 , wherein the aluminum composite powder has a particle size that is less than about 30 microns. 
     
     
       15. A radiation shield comprising the aluminum alloy of  claim 8 . 
     
     
       16. A process for making an aluminum nano-composite comprising:
 a) providing an aluminum powder having an oxide content between about 0.1 wt. % and 4.5 wt. %; and 
 b) hot-working the aluminum powder such that a microstructure grain size of the aluminum powder is reduced by a factor of at least 10 to form an aluminum nano-composite. 
 
     
     
       17. The process of  claim 16 , wherein the hot-working is performed at a temperature below the recrystallization temperature of the aluminum powder. 
     
     
       18. The process of  claim 16 , wherein the oxide content is derived from a natural aluminum oxide formation layer on the aluminum powder. 
     
     
       19. The process of  claim 16 , wherein during step b) the natural aluminum oxide is distributed throughout a microstructure of the aluminum powder. 
     
     
       20. The process of  claim 16 , wherein the aluminum nano-composite is subsequently formed into a radiation shield.